The present invention relates generally to pumps for filtration systems used in industrial applications, such as cleaning machine coolant containing contaminants and machining chips and returning clean coolant to the machine tools for reuse, and particularly relates to pumps and apparatus and methods for mounting the pumps in relation to the filtration tanks used in such systems such that the pumps are readily and easily removed from service and reinstalled in the filtration systems.
As will be recalled from a review of my prior application Ser. No. 144,058, identified above, the disclosure of which is incorporated herein by reference, filtration tanks for such industrial applications are generally set below elevation such that the contaminated liquid and machining chips may flow from the machine tools to the tanks. In the tank, the larger and heavier machine tool chips and other debris tend to settle to the bottom of the tank and a dragout conveyor system or other mechanical means are employed to convey the chips and resulting swarf from the tank for removal. Filters are employed in the tank to separate the smaller chips and other contaminants from the coolant. One well-known and commercially successful filtration system used for this purpose is sold by the assignee hereof, Henry Filters, Inc., and employs one or more horizontally disposed, generally cylindrical, filter drums located adjacent the bottom of the tank. A suction is provided to the interior of each filter drum to pull coolant from the tank through the filter element and deliver clean coolant to a clean coolant compartment which forms a part of the filtration tank. Filter cake, comprised of small chips and other contaminants, is thus formed on the outside of the drum surface. Periodic indexing of the filter drum in conjunction with a doctor blade removes portions of the accumulated filter cake, which drop to the bottom of the tank for removal, as shown in Applicant's U.S. Pat. No. Re 32,135.
As stated in the prior application, vertical turbine-type pumps are frequently used, along with other types, to pump the clean coolant from the clean coolant compartment of the filtration tank to the machine tools. Those pumps, from time to time, require periodic service and maintenance. To remove a pump of that type from a filtration tank involves considerable labor, downtime, and the services of a number of different types of skilled tradesmen, all of which adds to the expense of the system. The problems associated with the removal of those types of pumps are outlined in greater detail in my prior above-identified application and its subject matter is directed generally to replacement of such pumps with novel and improved pumps and ancillary mounting apparatus therefor.
One solution to those problems, as disclosed in my prior application, provides a pump head with the drive motor therefor being of the submersible type and submerged with the pump below the coolant level. Another solution provides a drive motor separable from the pump which is disposed above the coolant level in the tank with a disconnectable driveshaft coupling the drive motor to the pump head. In those embodiments, the pump has its suction inlet port receivable in a suction receptor ring adjacent the bottom of the clean coolant tank. The discharge head of the pump is also receivable in an annular housing fixed in the tank and which housing forms with the discharge head an annular chamber in communication with a fixed discharge outlet conduit. In accordance with the invention disclosed in that prior application, the pump suction and discharge connections are effected simply by lowering the pump into the tank. No bolting, pipe connections or further movement of any of the elements of the pump or tank to effect the two pump connections are required. Likewise, the removal of the pump is accomplished simply by lifting the pump from the tank, similarly without physically disconnecting the pump and pipe connections in the tank, for example, by unbolting or the like. Various forms of the above-described invention are set forth in the prior patent application and each disclosed embodiment specifically has a vertical pump orientation, i.e., the axis of rotation of the impeller is generally vertical.
In accordance with the present invention, a horizontal pump orientation may also advantageously be used such that the suction and discharge sides of the pump can be connected and disconnected relative to the tank, for example, through a side wall of the tank. That is to say, the horizontal pump orientation enables the pump to be mounted external to the clean tank with the suction side of the pump communicating with the clean filtrate similarly as described in the prior application. Significant advantages are afforded by a horizontal pump mounting For example, in many installations, there is insufficient headroom or headroom barely sufficient to remove, with difficulty, the pumps in a vertical direction from the tanks. Where headroom is at a premium, oftentimes space to one side of the tank is not, and is therefore available. Consequently, a side-mounted, horizontally oriented, pump installation which could be readily installed and removed, affording similar advantages as the vertical pump orientation specifically disclosed in my prior application is highly beneficial. Moreover, such horizontal pump orientation may be used with tanks which are either below elevation or at elevation, i.e., sitting on the floor of an industrial facility. An additional advantage resides in the ability to use an externally mounted motor, which, for example, could be an air-cooled motor, to drive the pump. A submersible motor may also be used under conditions where there is risk of flooding of the motor. Additionally, the horizontal orientation can be easier to retrofit in existing installations than the vertical pump depending on the accessibility of the tank.
To accomplish the foregoing and in accordance with the present invention, there is provided a filtration tank, preferably, but not necessarily, having a clean compartment in which there is provided a side opening in communication through a tank outlet conduit with the filtrate in the clean coolant compartment of the tank. The side opening preferably includes a receptor ring for receiving the suction inlet port of the pump. Suitable seals are provided between the receptor ring and the pump inlet port to seal the inlet port and the side opening of the tank one to the other upon installation of the pump. There is additionally provided a fixed housing comprised of an enclosure in the form of an annulus having a fixed outlet conduit in communication with a manifold for flowing clean filtrate from the pump discharge for return to the machine tools. The pump includes an impeller between its inlet port and discharge head. The pump discharge head includes a pair of axially spaced end walls in part defining an annular chamber for receiving clean filtrate or coolant from the pump inlet port.
When the pump is mounted in the housing and inlet port is disposed in the receptor ring, the annular housing and the end walls of the pump discharge head form the annular chamber in communication through the impeller and pump inlet port with the filtrate in the clean coolant compartment. Consequently, when the pump is actuated, filtrate may be pumped through the pump inlet port and into the annular chamber formed by the housing and pump discharge head for flow through the fixed outlet conduit and return to the machine tools.
In accordance with the present invention, the pump is removably mounted relative to the housing and tank. Specifically, the pump is disposed on a generally horizontal axis coincident with the impeller axis. The size of the inlet port and impeller are such that those elements may be displaced through the annular housing. Thus, to install the pump, the inlet port and impeller housing are first inserted through the annular discharge housing. The pump inlet port is then received in the receptor ring in the side wall opening of the tank. At the same time, the end walls of the pump discharge head are marginally sealed against the horizontally oriented annular discharge housing, thereby completely enclosing the annular discharge chamber. A valve assembly is disposed in the tank outlet conduit such that, when the pump is not operating, the valve is closed to prevent leakage of air into the tank, and upon removal of the pump from the tank, the valve prevents the flow of filtrate toward the opening of the tank.
To remove the pump, for example, for servicing and maintenance, the valve assembly is closed and the pump is withdrawn in a generally horizontal direction away from the tank, generally parallel to the axis of rotation of the impeller such that the pump discharge head is removed from the annular housing. Upon such movement, the impeller and suction inlet port of the pump are also withdrawn and similarly pass through the annular housing. Once the maintenance on the pump is performed, the pump may be readily reinstalled. To accomplish this, the pump is inserted through the annular housing, inlet port end first, until the end walls of the pump discharge head mate and seal against the housing and the inlet port seals in the receptor ring. Suitable clamps are provided to clamp the pump to the housing to secure the pump in final installation. In that position, the pump inlet port is sealed to the tank outlet. Upon opening the valve assembly, and operating the pump, the filtrate flows from the tank through the pump to the manifold for return to the machine tools.
Similarly, as indicated in my prior application, the present installation and removal does not require bolting or unbolting of the pump or pipe connections nor does it require the services of skilled craftsmen. The suction and discharge connections and disconnections are effected automatically, in both instances, simply upon generally horizontal displacement of the pump in respective opposite directions. It will also be appreciated that the discharge housing is preferably external to the tank and fixed either to the tank or to ancillary support structure separate from the tank. Alternately, the discharge housing may be an integral part of the tank, similarly as in my prior application, but oriented horizontally rather than vertically. In this latter configuration, the discharge housing as well as its outlet conduit and the manifold may be disposed within the tank, the housing being accessible to the pump externally of the tank.
In accordance with a preferred embodiment of the present invention, there is provided apparatus for pumping liquid, comprising a tank for containing the liquid, a pump for pumping liquid from the tank and having an inlet port, a discharge head and an impeller mounted for rotation about a generally horizontal axis for supplying liquid from the tank through the inlet port to the discharge head. Means carried by the pump head define at least in part a chamber for receiving the liquid discharge from the head and means are provided for removably connecting the pump to the tank. These connecting means include a housing for encompassing at least in part the pump discharge head and an outlet conduit connected to the housing, the housing defining in part the chamber when the pump is connected to the tank whereby liquid may be pumped from the tank into the pump inlet and the chamber for discharge into the outlet conduit. The pump inlet port is of a size to pass through the housing upon displacement of the pump in the direction of the horizontal axis thereof to remove the pump from the tank.
In another aspect of the present invention, there is provided, in a tank for containing a liquid, a filter having a suction side, communicating means in communication with the suction side of the filter, a discharge outlet conduit, and a pump having an inlet port, a discharge head, and an impeller, the pump being disposable on the suction side of the filter in communication with the communicating means for suctioning liquid from the tank through the filter, the communicating means and the pump inlet port for discharge through the discharge head into the discharge outlet conduit, a method of installing the pump in communication with the filtrate on the suction side of the filter, comprising the steps of (a) positively effecting below the level of liquid in the tank a suction connection between the pump inlet port and the communicating means; (b) positively effecting a discharge connection between the discharge head and the outlet conduit and (c) wherein steps (a) and (b) are accomplished by displacing the pump in a generally horizontal, direction.
In an alternative embodiment of the invention, a container is provided which is adapted to receive the pump. In this embodiment, the container has an annular enclosure for receiving and mating with the discharge head. The container is then secured to the tank and the pump may still be inserted and removed through the container. In this embodiment, a receptor ring is not required for the inlet suction port. A valve assembly is also included and may be secured to the container which is then secured to the tank. The valve assembly may also be within the tank such that when the pump is shut off or removed the valve assembly is closed.
Accordingly, it is a primary object of the present invention to provide a novel and improved pump and apparatus and methods for its installation and removal in an industrial filtration system whereby the pump may be readily and easily installed and removed from the filtration system in a generally horizontal direction.
These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, appended claims and drawings.